handle erroneous epop max size

src/lib.rs

@@ -11,6 +11,7 @@ pub enum ReadError {
 pub enum Error {
     Read(ReadError),
     BadPopSize,
+    BadEpopMax,
     BadMut,
     BadCrossRatio,
     BadMove(Pos),
@@ -87,6 +88,7 @@ impl std::fmt::Display for Error {
         match self {
             Error::Read(e) => write!(f, "{e}"),
             Error::BadPopSize => write!(f, "population size cannot be 0"),
+            Error::BadEpopMax => write!(f, "elite population size must be less than pop size"),
             Error::BadMut => write!(f, "mutation length too large"),
             Error::BadCrossRatio => write!(f, "crossover ratio cannot be 0"),
             Error::BadMove(pos) => write!(f, "invalid move ({pos})"),
@@ -552,6 +554,10 @@ pub fn run(config: Config, rle: Option<String>) -> Result<()> {
         return Err(Error::BadPopSize);
     }
 
+    if config.epop_max >= config.pop_size {
+        return Err(Error::BadEpopMax);
+    }
+
     if config.mut_max > config.dna_size {
         return Err(Error::BadMut);
     }